This topic has been posted before, but Roku support always closes before resolving.
My Roku Express is missing Search and apps like Amazon Prime & Disney+ even though these services are available in my region. (Australia)
This functionality is advertised in my region, so it should be available because that's what I purchased.
Do I need to return the device for a refund because it's region-limited?
Here's a thread with the search answer (currently right below your thread so maybe you already saw it).
Also Australia is not a supported region at all, so, sorry but "what you get is what you get".